Ubisoft Error Dolphin 028 | Proven Fixes

The Dolphin-028 error is a connectivity issue with Ubisoft Connect (the launcher). It means your PC cannot exchange the necessary “handshake” data with Ubisoft’s authentication servers.

This error affects multiple games (including Rainbow Six Siege, Ghost Recon, and The Division 2) because it blocks you from logging in entirely.

Here are the proven fixes, ordered from easiest to most effective.

Fix 1: The “Cache Clear” (Most Effective)

Corrupted temporary files in the launcher often cause this loop.

1. Close Ubisoft Connect completely (check your taskbar/system tray to make sure it’s not running in the background).

2. Navigate to this folder on your PC: C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher\cache

3. Delete the contents of the cache folder. (Or rename the folder to cache_backup if you want to be safe).

4. Restart Ubisoft Connect.

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Fix 2: Flush Your DNS

If the cache clear didn’t work, your network settings might be holding onto a bad connection path.

1. Press the Windows Key and type cmd.

2. Right-click Command Prompt and select Run as Administrator.

3. Type the following commands one by one, pressing Enter after each:

   • ipconfig /flushdns

   • ipconfig /release

   • ipconfig /renew

   • netsh winsock reset

4. Restart your computer and try again.

Fix 3: The “Hotspot Jump” Workaround

If your home router is blocking the specific authentication port, this bypasses it.

1. Disconnect your PC from your home Wi-Fi/Ethernet.

2. Turn on a mobile hotspot on your phone and connect your PC to it.

3. Launch Ubisoft Connect and log in.

4. Once you are successfully logged in and can see your games, switch back to your normal home Wi-Fi/Ethernet. The connection usually stays active after the initial login.

Fix 4: Check MTU Settings (Advanced)

If you still can’t connect, your packet size (MTU) might be too high for Ubisoft’s servers.

1. Open Command Prompt as Administrator.

2. Type: netsh interface ipv4 show subinterfaces

3. Note the name of your connection (e.g., “Ethernet” or “Wi-Fi”).

4. Type this command to lower the MTU to 1450: netsh interface ipv4 set subinterface "Ethernet" mtu=1450 store=persistent (Replace “Ethernet” with your actual connection name).

Note: If none of these work, check Ubisoft Support on X (Twitter). If their authentication servers are down globally, you just have to wait.